But retailers from large supermarket chains to small grocers are not required to keep eggs in cold storage, even though research shows it could help stop the spread of potentially deadly salmonella bacteria.

"Egg-associated outbreaks of salmonella have been increasing – that is clear," said Associate Professor Martyn Kirk, an expert in epidemiology at the Australian National University.

He said it was crucial for supermarkets to think about cold storage and egg-related salmonella prevention because the risk of an outbreak, leading to serious illness and hospitalisation, can arise at any point from the farm to the home.

"It is a priority. We've seen lots of outbreaks. We should be doing multiple things to try and prevent salmonella occurring."

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Eggs are not being kept in refrigerated cabinets in some retail stores, as seen in this Box Hill store in Melbourne. Photo: Daniel Pockett

Salmonella bacteria is found on birds with the germ usually spreading to eggs through faeces.

Under food safety laws, Australian eggs are washed, inspected for cracks, graded and kept in cool rooms on farms before being transported in refrigerated trucks to reduce the risk of bacterial survival.

But Brian Ahmed, president of the egg group at the Victorian Farmers Federation, said keeping eggs refrigerated in supermarkets remains the "missing link" in the food safety chain.

"It should be treated exactly like raw meat – don't look at an egg any different way," he said.

Connor Thomas, adjunct senior lecturer in microbiology at the University of Adelaide, also urged grocery stores to keep eggs in a cool environment.

"That way you minimise the growth, increase the storage time, and minimise the risk," Dr Thomas said.

The calls come as the rate of salmonella infections rises across the country, with up to 40 per cent of cases linked to contaminated eggs.

In 2015 there were 58 cases per 100,000 people in Victoria, twice the infection rate of 10 years ago, health department data shows.

A total of 3404 people in Victoria suffered salmonella poisoning in 2015 – almost 2000 more than a decade earlier.

The National Notifiable Diseases Surveillance System figures also show that the first three months of the year are a peak period for infections.

A total of 36 per cent of salmonella notifications since 1991 were recorded between January and March each year.

The largest outbreaks tend to be at restaurants, which serve food made from raw egg products like tiramisu or aioli.

But an Australian Egg Corporation study also found inappropriate storage in retail stores can substantially increase the risk of salmonella with bacterial growth occurring within 10 days in eggs stored at 22 degrees.

"Given that commercially produced and graded eggs are given a shelf life of up to 37 days, there is a risk to consumers that eggs will contain substantial numbers of salmonella," the 2006 study, led by Dr Thomas, concluded.

Major grocery stores, however, have taken differing views on the issue since there is no legal requirement to keep eggs refrigerated like the United States and Canada.

Coles released a one-line statement when asked about its stores keeping eggs on shelves: "Coles adheres to all health and safety regulations regarding egg storage."

But supermarket rival Woolworths pledged it would move all of its eggs into refrigerated cabinets – and had already done so at many stores.

"As we roll out our store refurbishment program across the country, any remaining stores will move to refrigerated displays for all fresh eggs," a company spokesman said.

Wholesaler Metcash, a major supplier for IGA, said it urges store owners to keep eggs below 5 degrees, but it's not known how many follow the recommendation since stores are independently operated.

In a statement, ALDI did not disclose if any of its stores keep eggs in refrigerators.

Woolworths said it will move all eggs into cold storage while rival Coles said it adheres to all health and safety regulations regarding egg storage. Photo: Quinn Rooney

Food Standards Australia New Zealand last updated egg safety laws in 2011, but left out a retail requirement for cool storage because it concluded temperature was not a factor in spreading salmonella here if eggs are clean and intact.

A spokeswoman said the strain of salmonella present in Australia cannot grow on egg shells, though it could contaminate other foods or get inside the egg when its protective membrane breaks down or the egg is cracked.

"It was acknowledged that refrigeration during retail storage may enhance the quality of eggs," she said.

"However, this option was excluded early in the standard development process due to the nature of egg shell contamination in Australia and the substantial cost of implementing such an option."

But Dr Thomas said eggs have been continually implicated in illness and it's difficult to predict when an outbreak is going to happen, so it is vital to maintain a chain of food safety protection.